As the molten plastic is extruded from the nozzle it is either laid down on a print bed or onto another layer of filament that has been previously extruded. Because it is hot it adheres to the print bed, and fuses to the filament already laid. Hence the term FDM, Fused Deposition Modelling. The most common size of filament is 1.75 mm diameter and is extruded from a 0.4 mm nozzle, less common filaments can be as big a 3 mm diameter and extruded from a 1 mm nozzle.
Once you have designed your model it needs to be exported in an appropriate format, the most common format is an STL (Stereo Lithograpghy) file. You can open the model in slicing software which will create a file that the printer can read and therefore print your product.
In the slicing software, your product will be chopped up into horizontal slices or layers parallel to the print bed. The thickness of each of the layers is specified by the user in the slicing process and can be as thin as 0.06mm up to 0.6mm as long as an appropriate sized nozzle is installed in the printer.
The smaller the layer height the finer the surface finish, and conversely the thicker the layers the more coarse the finish will be. There is however a trade off in the time it takes the object to print. In the example below printing at a layer height of 0.06 mm the printing time is 21 minutes using 34 cm of filament, printing at 0.2 mm the print time is 5 mins and 33 cm of filament.
Here you can see the layers which are 0.2 mm high, you can also see part of the infill which is set at 10%. This object is quite small at 40 mm long x 6 mm wide x 6 mm tall and was a replacement neck bridge for a friend’s guitar so he could let his young daughter play as the previous bridge was too tall for her, it was also switched for left handed use.
For Christmas I purchased a bat detector kit for my partner, the kit made by Haynes is designed so the box it comes in is the box that you put the components into. As this is cardboard, I though this is just asking to have a custom made box that will better protect the sensitive electronics as well as being more robust for when it's in a backpack etc.
So grabbing my trusty calipers I set to work on designing the new case.
The case came out quite well, although I was a little disappointed with the front finish, but that’s down to me adding the raised ‘bat’ emblem on the front and then printing face down, lesson learned!
I have recently purchased a 3D scanner that enables me to scan objects and print them. Just for fun I scanned a friend from work as a test to see what the result would be.
As you can see below, the initial scan was quite rough and ready, however after some post scan processing in Meshmixer software I was able to create a very clean model. There were some holes that needed repairing but the level of detail is very good, even picking up the folds in the hoodie.
From left to right,
Original Scan;
Reworked in Meshmixer software;
During printing of the larger bust;
The final results.
So here you can see the stages from initial scan, to cleaning and reworking, to printing and so the final result. The smaller of the busts was printed as a test and took 2 hours, the larger took 6.5 hours!
I hope you found this little article interesting, if you have any questions please let me know and I will do my best to answer them.
Dean